Cycloruthenated complexes from iminophosphoranes: Synthesis, structure, and reactivity with internal alkynes

Cycloruthenated complexes [(η6-arene)Ru(C6H 4-2-PPh2=NR)Cl] (arene = benzene, p-cymene; R = Ph, H) containing orthometalated iminophosphoranes have been obtained by transmetalation reactions from Hg(C6H4-2-PPh 2=NR)2 derivatives to [(η6-arene)Ru(μ- Cl)Cl]2. These complexes react cleanly with internal alkynes R 1C=CR2 (R1, R2 = Ph, Et, CO 2Me), KPF6, and CuBr2, yielding the 1,1,2-triphenyl-3,4-di(alkyl/aryl)-2,1λ5-benzazaphosphinin-2- ium heterocycles [C6H4-PPh2-NPh-C(R 1)=C(R2)-3,4]+ as PF6 salts. In all studied cases only the monoinsertion products have been observed. In the case of the asymmetric alkyne MeC=CPh the insertion is regioselective, and the [C 6H4-PPh2-NPh-C(Me)=C(Ph)-3,4]PF6 salt is obtained. © 2011 American Chemical Society.Funding from Ministerio de Ciencia e Innovación (Project CTQ2008-01784, Spain) and Gobierno de Aragón (PI071-09) is gratefully acknowledged.Peer Reviewe